Focusing mechanism for projectors



S. STALBERG. FOCUSING MECHANISM FOR PROJECTORS.

APPLICATION FILED NOV. 20, 1920.

Patented July 11, 1922.

SVEN STALBERG, OF

UNHTETD) STATES Parent entice.

'NAHANT, rvrAssAciiusE'rrs, ASSIGNOR 'ro GENERAL Emoraro COMPANY, A ooaroaa'rron or NEW YORK.

Specification of Letters Patent.

Patented July 11, 1922.

Application filed. November 20, 1920. Serial No. 425,490.

naling lamps and the like.

An object of my invention is to provide improved means whereby the source of light may be adjusted to positions on or parallel to the axis of the reflector.

Another object of my invention 1s to provide an adjustingmechanism by. which the source'of light may be movedin planes concentric with the axis of the reflector.

A further object of my invention is to provide a mechanism whereby the source of light will be maintained at all times with its axis parallel to the axis of its original position.

,My invention will be better understood from the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

In the accompanying drawings; Fig. 1 is an elevation of a signalling lamp partly in section embodying my invention; Fig. 2 is an elevation of a clamping member and Figs. 3 and 4 are diagrams indicating several positions which in use my adjusting mechanism may assume.- 7

Referring to the drawing, the numeral 10 indicates a signalling lamp unit, having a casing 11, closed at one end by a wall 12 and open at its opposite end which is 'provided with a window 13 hinged at 14. The lamp unit is also provided with a handle 15 and a suitable sighting mechanism 16, partly visible in the drawing, but which forms no part of my invention. Within the casing 11, there is suitably mounted a reflector 17 preferably parabolic in form, having a central opening 18. The wall 12 is also provided with a central opening 19 concentric with the opening 18 of the'reflector. A

tubular socket member 20 extends through the openings 18 and 19 and supports a. source of light 21 within the reflector. This source I have shown as an incandescent lamp which is preferably secured to the socket member 20 by a bayonet slot arrangement indicated at 22. The electric circuit is through conductors 23 which enter the casing 11, pass through an opening in the wall 12 and extend into the tubular member 20 to the socket portion thereof, as shown.

The member 20 is supported by two clamping jaws 24, 25, which are provided with round openings through which said member extends. While the jaws 24 and 25 could both be formed alike, each having the form shown in Fig. 2, yet, in order to form a better gripping surface on the member 20, 1 preferably form one of the jaws, 25, with two prongs each havin a central opening, so arranged that the c amping jaw 24 will fit between the pron of the jaw 25. It will thus be seen that t e socket member 20 is supported at two points by the jaw 25 and at a third point intermediate said .two points by the jaw 24.

j The clamping jaws 24, 25, are each provided with longitudinal slots 26, 27, respec tively. The jaw 24 is slidably and pivotally connected to the wall 12 by a set screw 28. The jaw 25 is slidably and pivotally connected to the wall 12 by bolt 29, and is provided with a set screw 30 arranged to en age the clamping jaw 24, as shown.

rom theforegoing description, the operation of my adjustin ,.mechanism will be readily understood. l ormally the lamp 21 may be moved toward and away from the focal plane of the reflector by moving the socket member 20 through the openings in the clamping jaws, which are arranged to permit a free movement of said member. This-free movement may be checked, however, by means of the screw 30 which causes the jaws 24, 25 to grip the socket member 20 in op osite directions. The source of light ,may e moved in a vertical plane by reason is possible by reason of the pivotal connec- 11c 28 is tightened to hold the socket in a fixed relation with respect to the reflector, and the screw 30 is tightened to hold the jaws 24 and in such fixed relation to each other as to grip. the socket member. It is, of course, understood that the openings 18, 19

are of suitable size to permit the required latitude of movement for adjusting the lamp. It is to be observed that the wall 12 is parallel to the directrix of the reflector and 1 that the jaws 24 and 25 are arranged to hold length and width when it may be desirable and to th directrix.

the socket member 20 at right angles to said directrix. The consequence of this arrangement is, that any lateral movement given to the socket member 20 will be in a plane par- Thus, for instance, when the clamps are loosened, the socket member and with it the lamp may be given any lateral movement, such as indicated in dotted lines in Fig. 3 within the range permitted by the openings 18, 19, and slots 26,

27, and all these movements will be in planes parallel to the direotrix. This is a particularly desirable adjustment with lamps in which the filaments extend to a considerable my hand this 18th da 4 ViEN STALBERG.

that a selected part of the filament be placed in the focus of the reflector.

While I have described my invention as embodied in concrete form in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth inlthe annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. An adjusting mechanism for lamps and the like comprising a supporting wall having an opening, a lamp socket member loosely extending through "said opening, clamping members having longitudinal slots slidably and pivotally connected to said wall and arrangedto support said socket memher and permit its axial and lateral adjustv ment in any direction arallel to itself, and means for securing sa1d socket member in any adjusted position.

2. An adjusting mechanism for lamps and the like comprising a supporting wall having anopening, clamping jaws slidably and pivotally connected to said wall having openlngs'corresponding to the opening. in'the Wall, a tubular member extending through said wall opening and supported by said jaws, means'for adjusting and securing said jaws in any position along said wall, and means for securing said jaws in any position with respect to each other.

In witness whereof, I have hereunto set of November, 1920; 

